This invention relates generally to pointing devices and, more particularly, to an ergonomic pointing device.
Pointing devices such as computer mouse devices are commonly used, for example, to control cursor movement on a computer screen. The use of pointing devices often involves highly repetitive hand and finger movements and positions. Some forms of repetitive stress disorder may be attributed to the use of pointing devices, particularly where awkward and stressful movements and/or positions are involved. Pointing devices having configurations that force the wrist, hand, and fingers of the user to assume awkward and stressful positions and/or movements are undesirable.
Existing mouse devices have evolved with ergonomic considerations in mind. Assignee""s own U.S. Des. Pat. No. 411,837 shows a shape that guides the hand away from full pronation.
U.S. Pat. No. 4,862,165 to Gart discloses a mouse having an arched metacarpal-phalangeal support surface for supporting the anterior surface of the hand and a concave thenar pad support surface for supporting the thenar pad of the hand.
U.S. Pat. No. 5,726,683 to Goldstein et al. discloses a mouse having a top surface, a right side surface, and a substantially vertically rising left side surface. The top surface has a negative slope from front to rear in a range of 15-30xc2x0 and from left to right in a range of 20-30xc2x0, and provides at the front of the top surface a phalanx support. The top surface includes a peak running from front to back oriented to lie under the operator""s thenar eminence providing support thereto and a surface through which the operator can push the mouse with his or her thenar eminence.
U.S. Pat. No. 5,576,733 to Lo discloses a mouse having an upright, primary finger-supporting surface for supporting all of the fingers of an upright hand in straight positions and in an upright stack. The mouse includes an opposite thumb-supporting surface for supporting the thumb.
U.S. Pat. No. 5,894,302 to Scenna et al. Discloses a mouse including an upper surface having a hump for supporting the triangular area of the hand encircled by the thenar region, the hyperthenar region, and the region below the metacarpal-phalangeal joints. The upper surface includes a tail having a rising portion to underlie and bear the pressure of the region of the user""s hand where the thenar and hyperthenar converge. The finger buttons in the front are elevated above the hump.
U.S. Pat. No. 5,414,445 to Kaneko et al. Discloses a mouse including a top surface having a bulge for supporting the metacarpal-phalangeal joint ridge. The mouse supports the hand such that the wrist rests on the working surface on which the mouse is disposed.
The present invention is directed to a pointing device that improves upon the prior art with a unique combination of features and new modifications to provide increased comfort to the user. The invention does so by providing a pointing device that supports the user""s hand to avoid extreme positions of posture ranges of the wrist and the fingers and joints of the hand such as, for example, wrist extension, full pronation of the hand, and abduction or adduction of the thumb. The device is further configured to reduce pressure applied to the carpal tunnel, and to minimize contact pressure on the sensitive areas of the wrist by elevating it above the working surface. As a result, the pointing device tends to promote more relaxed hand and wrist posture, minimize static muscle loading, and reduce physical stresses during operation of the pointing device.
In accordance with an aspect of the invention, a pointing device for use on a working surface includes a bottom configured to be placed on the working surface, and at least one finger-operated pointing member. In a specific embodiment, the pointing device is a computer mouse device.
The device includes an upper surface having a crown for contacting a palmar region of the palm of the hand of a user substantially at the metacarpal-phalangeal (MP) joint of the second digit and desirably at least a portion of the MP joint of the third digit. The crown is higher in elevation than remaining portions of the upper surface relative to the bottom. Because one of the more repetitive tasks in operating the device entails pressing buttons using the second and/or third digits which involves movements mainly around the MP joints of those digits, the crown advantageously provides primary support from those MP joints toward the wrist.
The upper surface extends from the crown downwardly in a forward direction toward the tips of the second and third digits to form a front region, downwardly in a rearward direction toward the wrist of the user to form a back region, downwardly in an inward direction toward the thumb to form an inside region, and downwardly in an outward direction toward the MP joints of the fourth and fifth digits to form an outside region. A transverse hump extends from the crown in the outward direction for contacting a palmar region substantially at the MP joints of the fourth and fifth digits (and possibly a portion of the MP joint of the third digit). The transverse hump slopes downwardly from the crown to guide the hand away from full pronation. The back region supports the hypothenar region of the hand.
The crown and the back region preferably are sufficiently high relative to the bottom to maintain the wrist above the working surface to promote a near-neutral wrist position with little or no wrist extension, and to minimize contact pressure against sensitive areas of the wrist due to prolonged contact with the working surface.
The back region slopes downwardly with a sufficiently large curvature in the rearward direction to substantially avoid contacting the carpal tunnel region of the palm, thereby reducing pressure on the carpal tunnel. For example, the back region is typically configured to avoid contacting at least the middle and proximal portions of the carpal tunnel but may contact the distal portion of the carpal tunnel. In a specific embodiment, the back region has a greater curvature in the rearward direction than the front region in the forward direction.
The back region includes a xe2x80x9cthenar voidxe2x80x9d to substantially avoid supporting the thenar region, so that the thumb is allowed to hang down in a substantially neutral thumb position and to move freely relative to the pointing device. This eliminates pressure and loading on the thenar region due to interference from a thenar support found in conventional mouse devices.
The crown and the back region desirably are sufficiently high in elevation to allow the distal phalange of the thumb to rest on the working surface in a rest position between the extreme positions of adduction and abduction. In a specific embodiment, the thumb is about half-way between adduction and abduction.
The front region may include buttons on which to place the second and third digits. The buttons are desirably aligned with the phalanges of the second and third digits, respectively. In this way, the digits can operate the buttons efficiently by pressing downward in a substantially neutral position without awkward or strained movements (i.e., abduction or adduction).
In some embodiments, the housing includes an inner side surface on which to place the thumb, and an outer side surface on which to place the fifth digit and possibly the fourth digit. The inner side surface includes an upper region with an inverted surface portion to face downwardly toward the distal phalange of the thumb. The outer side surface includes an upper region with an inverted surface portion to face downwardly toward the distal phalange of the fifth digit (and possibly the distal phalange of the fourth digit). The inverted surface portions provide convenient contact locations for the thumb and the fifth digit (and possibly the fourth digit) to lift the pointing device, thereby reducing the gripping or pinching force when the mouse is lifted. The device desirably has a center of gravity disposed between the inverted surface portion of the inner side surface and the inverted surface portion of the outer side surface. In this way, the device will remain level without tilting in the front-to-back direction during lifting by the hand.